With prosperous development of Internet technologies, especially popularization of the mobile Internet, a “connection” gradually becomes a basic resource and requirement of equal importance as air and water in the human society. A social network, the Internet of Things, and a smart city network that rapidly develop directly and technically represent a connection between “persons”, a connection between “objects”, and a connection between “a person and an object”. Based on this, various Internet applications and researches explode, for example, various applications of a mobile terminal, a 4K video, and virtual reality. These applications and technologies bring a high bandwidth requirement, and inevitably impose a higher requirement on a wavelength division network that functions as a pipeline.
The wavelength division network includes nodes and a link. Two nodes are connected to each other by using an optical fiber link, and transmit a signal. In a current wavelength division network, an optical fiber link is usually a single-core optical fiber. To be specific, an optical core (a light-guide fiber) used to transmit data is wrapped in the single-core optical fiber. A structure of the single-core optical fiber is shown in FIG. 1(a). To further improve a communication capability of a single optical fiber, a multi-core optical fiber currently draws increasingly more attention. The multi-core optical fiber is a transmission medium in which a plurality of independent optical cores (light-guide fibers) are wrapped in a single optical fiber. A structure of the multi-core optical fiber is shown in FIG. 1(b). Each core is similar to a single-mode optical fiber, and optical signals in different cores are independently transmitted.
A network that is formed based on the multi-core optical fiber may be referred to as a Space Division Multiplexing (SDM) network. However, an existing connection establishment method does not support the SDM network that is based on the multi-core optical fiber, and consequently a connection cannot be established in the SDM network.